Key words rehabilitation - prehabilitation - ballet - muscle strength
Practical Implications
Supplemental physical fitness training seems to have a beneficial effect on
injury rate for dancers
Supplemental training reduced the number of missed dance sessions
A wide range of training methods were implemented that had beneficial effects
possibly due to the relatively low physical fitness levels of dancers
Further studies using advanced methodologies (RCTs), or replication of
current studies, are required to improve intervention efficacy
Introduction
A number of previous systematic reviews have highlighted that dancers have a high
incidence of injury with chronic injuries being more prevalent than acute [1 ]
[2 ]
[3 ]
[4 ]
[5 ]. Despite movement differences between dance genres,
the most affected sites are the lower extremity and lower back [6 ]
[7 ]
[8 ]
[9 ]
[10 ], with fatigue, overwork, and repetitive movement
being reported as the main causes [5 ]
[10 ]
[11 ]
[12 ]
[13 ]. However,
inadequate physical fitness levels, such as muscular strength [14 ]
[15 ] and muscular
endurance[12 ]
[16 ],
have often been cited as principal causes of dance injuries. As a result, it has
been argued that optimal physical fitness for dancers may be as important as skill
development [17 ].
Research over the past two decades has started to examine the association between
physical conditioning and dance injuries [11 ]
[18 ]
[19 ]
[20 ]. Research also revealed that physical fitness
increases even improve dance performance without any unwanted effects on the
aesthetics of the art [21 ]
[22 ]
[23 ]. However, only a few studies
directly examined the relationship between physical fitness training interventions
and dance injury [24 ], and the evidence has not been
reviewed yet. Therefore, this present study aims to systematically review the
efficacy of physical fitness interventions programs and on dance injury across
different dance genres and participant skill levels.
Materials and Methods
Search strategy
Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses
(PRISMA, 2020) [25 ], the following databases were
searched: CINAHL, Cochrane Library, PubMed, Web of Science, MEDLINE, China
National Knowledge Infrastructure (CNKI), and related journals such as Journal
of Dance Medicine and Science (JDMS) and Medical Problems of Performing Artists
(MPPA) were used to search peer-reviewed published articles in English or
Chinese.
These electronic databases were searched using the Medical Subject Heading (MeSH)
terms, free-text words, keywords, and subheadings: (“Physical Fitness
[MeSH Terms]” OR strength OR condition* OR fitness OR power OR
endurance OR mobility) AND (Injuries [MeSH Terms] or Injury) AND (Dance*
OR Ballet OR “Hip Hop” OR Jazz).
A hand search of reference lists and citations to identify other studies was also
conducted. The whole searching process occurred over three months, from March to
June 2021.
Inclusion and exclusion criteria
Inclusion criteria incorporated peer-reviewed publications in English or Chinese.
These articles had to deliver physical fitness intervention training to impact
injury incidence in dancers, with no limitation of nature of the injury, injury
sites, injury severity, dance genres, the levels of dance, gender, and age. All
study designs were included from case studies to random controlled trials.
Exclusion criteria comprised non-peer-reviewed sources such as books, conference
proceedings, and thesis.
Database searches were downloaded into EndNote (ver. 20, Clarivate). Articles
were removed if they did not directly relate to the inclusion criteria if it was
not in either English or Chinese ([Fig 1 ]). There
are two stages when screening articles: we screened all titles and abstracts
(Stage 1) and then full texts were assessed for inclusion (Stage 2). Any
discrepancies between the two reviewers (YD and MW) were discussed and mutually
agreed decisions were reached. The selected articles were subsequently reviewed
in full.
Fig. 1 PRISMA Flow Diagram [25 ].
Methodological quality assessment
The included studies’ designs were ranked according to the Oxford Centre
for Evidence-Based Medicine [26 ]. Studies were
further analyzed using Strength of the Evidence for a Conclusion (GRADE) [27 ]. The GRADE evaluated five aspects: Quality,
Consistency, Quantity, Clinical Impact and Generalizability, and which gave five
outcomes: Good, Fair, Limited, Expert Opinion Only, and Not Assignable [28 ]. The risk of bias was evaluated using Kmet et
al. [29 ] checklist. Studies were scored on 14-item
that assessed the internal validity or the extent to which the design, conduct,
and analyses minimized errors and biases. The assessment of the included studies
was evaluated separately by two reviewers (YD and MW).
Results
Descriptive information
A total of nine studies (1998 to 2021) met the inclusion criteria from an initial
pool of 2450 publications, and a further one additional publication was
identified via a reference review of the included studies ([Fig 1 ]). These ten studies offered physical
fitness training for professional (n=3) and pre-professional dancers
(n=7) whose dance genres were ballet (n=7), contemporary
(n=3), DanceSport (n=1), hip-hop (n=1), and Korean
traditional dance (n=1). The sample sizes ranged between 5 to 62, ages
from 11 to 27 years, and most of them were females (F=117–119;
M=65–69). However, only six studies provided information on the
dancers’ injury status [30 ]
[31 ]
[32 ]
[33 ]
[34 ]
[35 ] and affected sites [32 ]
[33 ]
[34 ]
[35 ] prior to intervention ([Table 1 ]).
Table 1 Included studies description, Strength of Evidence
and Risk of Bias
Study
Cohort
Method
Strength of Evidence
Risk of Bias
Genre
Dance level
Age (yrs)
Gender
N
Design
Condition pre-intervention
Mean
Mean±SD
Actual score/ possible score
%
Long et al., 202126
Ballet
Professional
23
M=2 F=4
6
Cohort
Un-injured
3
3±0.7
11/22
50
Vera et al., 202032
Ballet
Professional
27
M=20 F=19
39
RCT
NR
4
3.8±0.5
15/28
53.6
Viktória et al., 201627
Ballet, hip-hop
Pre-professional
13
NR
62
Cohort
Un-injured
3
2.8±0.8
12/22
54.6
Welsh et al., 199828
Modern, ballet
Pre-professional
19
M=1 F=7
8
Cohort
Back pain history but not current
4
3.8±0.5
5/22
22.7
Kline et al., 201329
Ballet
Pre-professional
11–18
NR
5
Cohort
Back pain and radicular symptoms
3
3.2±0.5
8/22
36.4
Roussel et al., 201434
Modern, ballet
Pre-professional
20
M=6 F=38
44
RCT
NR
3
2.8±0.8
16/28
57.1
KiM et al., 201831
Traditional Korean
Professional
24
M=3 F=10
13
RCT
Grade 2 unilateral hamstring strain
3
3±0
15/28
53.6
Mistiaen et al., 201235
NR
Pre-professional
20
NR
27
Cohort
NR
3
3±0.7
12/22
54.6
Allen et al., 201333
Ballet
Pre-professional
23–26
M=25–29, F=27–29
52–58
Cohort
NR
2
1.6±0.6
15/22
68.1
Chong et al., 201130
DanceSport
Pre-professional
NR
M=8 F=12
20
Cohort
Ankle soft tissue injury
3
2.6±0.6
8/22
36.4
Summary
11–27
M=65–69 F=117–119
5–62
3
3.1±0.6
48.4±13.1
Age=average age or age range; N=Number of participants;
NR=Not Reported; M=Male; F=Female;
RCT=Randomize Control Trail
Study design and assessment scores
The included studies had a range of methodologies, including two randomized
controlled trial studies, one prospective randomized clinical trial, one
un-controlled trial, one mixed-methods quasi-experimental study, one
non-randomized longitudinal study, and four cohort studies. These studies
included four levels of evidence according to the Oxford Centre for Evidence
Levels [26 ], which were comprised of Level 1
(n=1), Level 2 (n=4), Level 3 (n=3), and Level 4
(n=2).
Based on five aspects of GRADE, the mean scores ranged from 3.8 [32 ]
[36 ] to 1.6 [37 ], and assessment scores were classified as Fair
(n=1), Limited (n=7), and Expert Opinion Only (n=2)
([Table 2 ]). The overall scores of the risk
of bias to the method ranged from 68.2% to 22.7% (mean:
48.7%±13.1%) ([Table 1 ],
Supplemental Table A and B ).
Table 2 Physical Test, Intervention and
Results
Studies
Physical Fitness Test
Physical Intervention Training
Results
Training
Exercises
Intensity
Physical Fitness
Mean±SD (Pre vs Post; E vs C)
P value
Long et al., 202126
Motor control test, balance test, and stability tests on
knees and ankle, hip and upper extremity.
Agility and strength training
Bridges, planks, deadlifts, lunges, squats, step ups and
jumping
2-time/week 30-minute 5-week
Balance
260.1±18.0 vs 291.6±30.5
0.028*
Ankle and knee stability
119.6±12.3 vs 147.6±25.0
0.043*
Upper extremity stability
25.4±3.2 vs 31.3±4.3
0.042*
Vera et al., 202032
Balance test, turnout test, hypermobility test
Resistance training (with elastic bands or free weights)
Bridges, planks, deadlifts, lunges, squats, step ups,,
jumping; fire hydrants; resistance band toe points, foot
flexion and pointed eversion; Star drill; lower extremity
stretching; Nordic hamstring; dead bird and dog; Prone leg
lift; Glute kicks; Wall sits; Step-downs; Single-leg
stance.
3-time/week 30-minute 4-week
NR
NR
NR
Viktória et al., 201627
Static core strength test, motor control stability test.
Core strengthening and stretching, balance and lumbar motor
control. Correct dance posture.
NR
NR NR 12-week
Core muscles static strength (Ballet)
58.9±30.5 vs 88.7±21.3
0.00†
Core muscles static strength (Hip-hop)
67.6±32.5 vs 83.7±25.7
0.015†
Lumbar motor control (Ballet)
5.3±0.3 vs 3.7±0.3
0.00†
Lumbar motor control (Hip-hop)
4.0±1.3 vs 3.9±1.0
0.000†
Welsh et al., 199828
Spine (back) extensor strength test.
Back strengthening (abdominal, rotary torso, hip and knee
extensor, knee curl)
NR
2-time/week NR 7- to 10-week
Lumbar extensor strength
14% to 151%
NR
Dancers’ ratings of strength
2.5 vs 6.25
NR
Kline et al., 201329
Core strength and endurance test
Traditional lumbar stabilization and core strengthening
program
Plank, bridge
2-time/week 25–30-mins 6-week
Strength in positions
NR
NR
Straight leg raise range (PROM)
85 vs 111
NR
Roussel et al., 201434
Aerobic capacity test, lower limb explosive muscle strength
test
Endurance, strength, proprioception, motor control training,
circuit
Exercises on bicycles, steps, rowing machines, and
dance-specific exercises
2-time/week 75-minute 16-week
Aerobic capacity
211.1±3.4vs 202.1±3.6
0.079
Explosive strength
1.83±0.03 vs 1.81±0.03
0.630
KiM et al., 201831
Flexibility and isometric strength of the hamstring muscle
test
Postural stabilization, Concentric and eccentric ROM
Static and active stretching, straight leg raising, leg
curls, anterior and posterior pelvic tilt.
3-time/week NR 8-week
Flexibility and Strength
121.9±8.4 vs 139.6±5.9
<0.001†
Mistiaen et al., 201235
Aerobic endurance test, explosive muscle strength of lower
limbs test
A circuit (endurance and strength),
“Start-To-Run” program.
Dance-specific exercises
3-time/week 90-minute 24 weeks
Aerobic power
2.3±0.6 vs 2.4±0.6
0.025*
Oxygen consumption
1.6±0.5 vs 1.7±0.5
0.045*
Resistance level
129.6±40.5 vs 139.8±43.5
0.019*
Strength increased
NR
NR
Allen et al., 201333
Strength test (core strength and lower limbs), shoulder and
trunk (rotary) mobility test.
Strength and conditioning (cross-training, resistance
training).
Jumping and NR
NR NR 144-week
Functional Movement Screen
15 vs 13
>0.05
Chong et al., 201130
AROM and PROM test
Ankle muscle strength (resistance training), ROM,
proprioception
Ankle flexion and extension, Power bike exercise,
closed-chain exercise, diagonal, heel lift, jumping, balance
exercise on device
7-time/week ~75-minute 6-week
Ankle Functional score
57.6±8 .7 vs 89.3±7 .9
<0.001†
AROM
21.5±5 .4 vs 59.7±15.2
<0.001†
PROM
33.3±6 .1 vs 67.9±11.9
* p<0.05 and †p<0.01;
NR=Not Reported; AROM=Active Range of Motion;
PROM=Passive Range of Motion; E=Experiment group;
C=Control group; SD=Standard Deviation;
Physical fitness tests and training
All studies did physical fitness tests pre- and post-intervention. The majority
of them did muscular strength tests [31 ]
[32 ]
[33 ]
[34 ]
[37 ]
[38 ]
[39 ]
(n=7), whilst other tests included stability [30 ]
[31 ]
[37 ] and balance [30 ]
[36 ], mobility [35 ]
[36 ]
[37 ] and flexibility[ 34], and cardiovascular endurance [33 ]
[38 ]
[39 ].
These physical intervention training included strength training [30 ]
[31 ]
[32 ]
[33 ]
[35 ]
[37 ]
[38 ]
[39 ]
(n=8), stability training (included balance training, motor control
training, stabilization training, proprioception training) [31 ]
[33 ]
[34 ]
[35 ]
[38 ] (n=5), mobility training [34 ]
[35 ]
(n=2), endurance training [38 ]
[39 ] (n=2) and agility training [30 ] (n=1).
Five studies reported their training methods were comprised of resistance
training [30 ]
[35 ]
[37 ], circuit training [38 ]
[39 ], and
cross-training [37 ]. In which there were
twenty-four exercise movements offered in their physical fitness training ([Table 2 ]).
Physical fitness training load and outcome
The studies that did provide detailed interventions reported that they mainly
lasted between 30–90 minutes per session [30 ]
[33 ]
[35 ]
[36 ]
[38 ]
[39 ]
(n=6), 2–3 times per week [30 ]
[32 ]
[33 ]
[34 ]
[36 ]
[38 ]
[39 ] (n=7) for 4–16 weeks [30 ]
[31 ]
[32 ]
[33 ]
[34 ]
[35 ]
[36 ]
[38 ] (n=8). Two studies
involved long-term interventions ranging between 6–36 months [37 ]
[39 ].
Post-intervention testing reported significant improvements in physical fitness
elements, this included stability and balance [30 ]
[31 ], strength [31 ]
[34 ]
[39 ], flexibility [34 ]
[35 ], and endurance [39 ]. Two studies reported non-significant
improvements in strength from 14% to 151% [32 ]
[33 ] and another
physical fitness parameters remained consistent ([Table
2 ]).
Physical fitness training and dance injury outcome
The majority of studies (80%) reported a positive improvement in injury
reporting. The eight studies stated that the physical fitness interventions had
a range of positive outcomes, for instance, a significant decrease (82%
reduction, p=0.002) in injury rate [36 ],
pain intensity (ballet: 9 vs 1.3, p=0.004; Hip-hop 8 vs 2.8,
p=0.002) [31 ], pain severity (4.2 vs 2.1,
p=0.017) [34 ], and injury count (355 vs
174, p<0.01; 5 vs 0, p=0.019) [37 ]
[38 ], and also a significant
increase in time between injuries (130 vs 219 days, p=0.028) [36 ]. Furthermore, two studies reported a
non-significant decrease in the numbers of dance activities missed due to pain
[32 ], relief of symptoms [33 ].
Two studies [30 ]
[39 ]
used the SF-36 questionnaire to track injuries, neither reported overall change
in SF-36 scores post intervention, but one noted a significant decrease in
physical pain (83.2 vs 67.6, p=0.009) [39 ]. The other study [30 ] recorded no
injuries during the study period.
Physical fitness interventions significantly decreased dancers’ injury
incidence across five different dance genres; Ballet [31 ]
[32 ]
[33 ]
[36 ]
[37 ]
[38 ], Modern [32 ]
[38 ], Hip-hop
[31 ], DanceSport [35 ] and traditional Korean [34 ] ([Table 3 ]).
Table 3 The Methodology and Results of Dance
Injury
Studies
Genres
Methodology of Dance Injury
Results of Dance Injury
Definition
Injury Tracking
Aspects
Mean±SD
P value
Differences
Pre or C
Post or Exp
Long et al., 202126
Ballet
Time-loss and time requiring modify dance activity.
Interview
Time-loss
0
0
NR
ND
Vera et al., 202032
Ballet
Full-time lose, adaptation of NASA injury guidelines.
Electronic medical record system
Injury rate was 82% less
0.52–0.90
0.18
0.022*
Decreased
Time between injuries
130
219
0.028*
Increased
Viktória et al., 201627
Ballet
Low back pain
Visual analogue scale (VAS)
Pain intensity (Ballet)
9.0±18.2
1.3±3.3
0.004†
Decreased
Hip-hop
Pain intensity (Hip-hop)
8.0±10.9
2.8±8.7
0.002†
Welsh et al., 199828
Modern and Ballet
The number of dance activities missed due to pain
(time-loss)
The number of dance activities missed due to back pain
The numbers of dance activities missed reduced
NR
NR
NR
Decreased
Kline et al., 201329
Ballet
Pain, strain, spasms, pull, tingling, numbness, weakness.
Patient Specific Functional Scale, Numerical Pain Rating
Scale
Relief of symptoms
NR
NR
NR
Decreased
Roussel et al., 201434
Modern and Ballet
Acute trauma; repetitive stress in dancing; missed dance
activities
VAS, Short Form 36-questionnaire
Less low back injuries (count)
5
0
0.019*
Decreased
Kim et al., 201831
Traditional Korean
NR
Hamstring injury questionnaire, VAS
Pain severity (VAS)
4.2±1.2
2.1±0.9
0.017*
Decreased
Mistiaen et al., 201235
NR
Symptoms forcing the student to interrupt classes
(time-loss)
Medical and the short-form 36 questionnaires, VAS
The total score of the SF-36 remained unchanged
663±105
612.7±122.6
0.122
ND
Allen et al., 201333
Ballet
Time-loss (≥24 hrs), classified either as traumatic
or overuse
Injury surveillance program (in-house physiotherapists)
Injury count
355
174
<0.01†
Decreased
Injury incidence (M)
4.76
2.22
NR
Decreased
Injury incidence (F)
4.14
1.81
NR
Chong et al., 201130
DanceSport
NR
Ankle Functional Score
Ankle circumference
26.4±2.9
24.8±2.8
<0.01†
Decreased
* p<0.05 † p<0.01;
ND=no difference after intervention; NR=not reported;
C=Control group; Exp=Experiment group;
SD=Standard Deviation;
Dance injury tracking methods
Eight studies defined dance injury[30 ]
[31 ]
[32 ]
[33 ]
[34 ]
[36 ]
[37 ]
[38 ] with 6 using a time-loss definition, including
dance activities missed and symptoms forcing the student to interrupt
classes[30 ]
[32 ]
[36 ]
[37 ]
[38 ]
[39 ]; and the other studies reported injury as pain, strain, spasms,
pull, tingling, numbness, weakness, acute trauma, or overuse injury[33 ]
[36 ]
[37 ]
[38 ].
The severity of dance injury was monitored using a number of scales that included
the Visual Analogue Scale [31 ]
[34 ]
[38 ]
[39 ] and Patient Specific Functional Scale and
Numerical Pain Rating Scale [33 ]. Injury incidence
and aetiology were tracked using the Short Form 36-Questionnaire [38 ]
[39 ] and Hamstring
Injury Questionnaire [34 ], and clinician and
dancer records (Electronic Medical Record System[36 ], Self-record [32 ] and Injury
Surveillance Program [37 ] and Ankle System
Functional Score [35 ]). One study [30 ] also incorporated interviews with their study
design ([Table 3 ]).
Intervention location, equipment and supervision
Seven studies reported where the intervention occurred these included the dance
studio [30 ]
[34 ]
[36 ]
[37 ], the clinic
[32 ]
[33 ]
[34 ], a rehabilitation laboratory [35 ], home [33 ], or
pool [37 ]. Six studies had supervised
interventions by either a physician [32 ]
[33 ], physical therapist [30 ]
[32 ]
[33 ]
[34 ]
[38 ]
[39 ], fitness trainer[32 ], dance teacher/dancers [30 ]
[38 ]
[39 ]; while only one was un-supervised and used a
booklet, graphic and video [36 ]. Finally, three
studies did not report how the intervention was carried out [31 ]
[35 ]
[37 ]. The most popular item of equipment for the
interventions was a resistance band [30 ]
[34 ]
[35 ]
[36 ]
[38 ]
(Supplemental Table C ).
Discussion
This systematic review aimed to examine the efficacy of physical fitness intervention
training programs on dance injury across different dance genres and participant
skill levels. It was found that such programs led to decreased dance injuries [30 ]
[31 ]
[33 ]
[34 ]
[35 ]
[36 ]
[37 ]
[38 ]
[39 ]. Although 80% of the identified studies
reported a positive effect, the number of these studies (n=7) and their
sample size were rather limited. Furthermore, the quality of these studies was rated
between Fair to Expert Opinion Only, and scores of the risk of bias ranged from
68.2% to 22.7%, with only two Randomized Controlled Trail studies
[36 ]
[38 ].
Although physical fitness training significantly reduced dance injuries across the
included studies, no meta-analysis could be performed (heterogeneity) and therefore
the evidence is based on few or individual studies. For instance, injury rate
(p<0.05) [36 ], extended time between injuries
(p<0.05) [36 ], reduced pain intensity
(p<0.01) [31 ], relieved pain severity
(p<0.05) [34 ], and reduced injury count
(p<0.01, p<0.05) [37 ]
[38 ], and decreased the circumference of swelling ankles
(p<0.01) [38 ]. However, the current level of
evidence highlights the need for improved methodologies, such as using an inclusive
injury definition and reporting full intervention details. Although six studies used
a time loss as dance injury definition [30 ]
[32 ]
[36 ]
[37 ]
[38 ]
[39 ], this could underestimate the injury burden as the
majority of dance injuries are minor or moderate and do not require time away from
dancing [40 ]
[41 ].
The majority of studies had limited sample sizes, using convenience samples, seven
studies had sample sizes smaller than 30 participants. No studies reported power
analysis a priori, which weakens the generalizability of the link between physical
fitness training and performance or injury risk [24 ].
Further, the lack of details regarding training frequency [31 ]
[37 ] and training load [31 ]
[32 ]
[34 ]
[37 ] means study
replication or clinical implementation is impossible.
For a study to have a clinical perspective, the length of the exercise intervention
and the number of participants was essential to provide relevance. Welsh et al.[32 ] recruited eight dancers for a 7–10 week
back strengthening intervention training and reported a non-significant reduction in
the numbers of dance activities missed from 16 to 4 sessions. In contrast, Allen et
al. [37 ] recruited 52 to 58 dancers over three years
and reported a significant reduction in injury counts from 355 to 183 in the second
year. However, the later study lacked specific intervention protocols, as they
implemented an individualized program approach. This study and another long-term
study [37 ]
[39 ] were also
limited due to their lack of a control group.
Vera et al. [36 ] attempted to implement a 52-week
randomized controlled study with a professional ballet company setting. The authors
reported an 82% decrease in injury rate and an extended period between
injury episodes, but these results can’t truly be put down to the
intervention due to the low compliance (45% dropped out) and completion rate
(4-week intervention). Home-based [33 ] or
self-executed intervention with a handout outlining [30 ]
[39 ] using portable apparatus [30 ]
[33 ]
[34 ] is undoubtedly convenient but goes against the idea
that unsupervised sessions [36 ] may be incorrectly
executed [24 ].
The majority of included studies (n=7) tested strength [31 ]
[32 ]
[33 ]
[34 ]
[37 ]
[38 ]
[39 ] and provided successful strength training
interventions [30 ]
[31 ]
[32 ]
[33 ]
[35 ]
[37 ]
[38 ]
[39 ],
but only a couple evaluated cardiorespiratory parameters in their conditioning
interventions [38 ]
[39 ].
However, previous research has shown that dance class and rehearsal are at a lower
cardiorespiratory demand than dance performance [42 ].
During the performance, dancers work at close to their maximum capacities [43 ]. This reinforces a link between poor
cardiorespiratory fitness, fatigue and injury incidence [19 ]
[44 ]
[45 ].
The lack of cardiorespiratory interventions within the included studies highlights
the need for a more holistic approach to injury prevention.
Intervention frequency and duration ranged between 2–3 times per week [30 ]
[32 ]
[33 ]
[34 ]
[36 ]
[38 ]
[39 ] and 30–60 minutes per time [24 ]
[30 ]
[33 ]
[36 ]
[38 ] which is often lower than other interventional
regimens. Unless their injury prevents dancing, dancers usually train
4–6 hours a day, 5–6 days [46 ]
a week, and therefore a limited intervention can produce beneficial effects [47 ]
[48 ].
Although the selected studies reported significant positive benefits for the use of
physical fitness training as an intervention, they used a variety of scales with
only pain intensity or injury severity in common [31 ]
[33 ]
[34 ]
[38 ]
[39 ]
[49 ]
[50 ].
These are both subjective scales, and more replicable methods are needed as the case
in sports injury surveillance [51 ].
The overall quality of included studies was relatively low. The majority demonstrated
inadequate sample sizes [30 ]
[32 ]
[33 ]
[34 ]
[35 ]
[36 ],
weak design [30 ]
[32 ]
[33 ], incomplete evidence [31 ]
[32 ]
[34 ]
[36 ], and very poor
execution [36 ]. Moreover, the methodological risk of
bias is high. Although the purpose of their studies was easily identified, half of
them failed to completely describe the purposes [31 ]
[32 ]
[35 ]
[36 ]
[39 ].
Some of them lacked inclusion/exclusion criteria of subject selection [32 ], or their selection strategy was not ideal [35 ]
[37 ]
[38 ]
[39 ], some
didn’t report the basic descriptive data (age or sex) of dancers [31 ]
[33 ]
[39 ], whereas in some studies statistical analysis was
not reported [32 ]
[33 ].
Therefore, the significant results reported in insufficient details with low
evidence [30 ]
[31 ]
[32 ]
[33 ]
[34 ]
[35 ]
[36 ] lack validity.
Conclusion
The included studies suggest that physical fitness training could positively affect
dance injury rate, injury intensity, injury severity, extend the time between
injuries, and reduce injury count. However, the heterogeneity of the studies, the
low sample sizes and weak methodological designs prevent a meta-analysis and
therefore evidence is based on few or single studies. Therefore, more RCTs with
high-quality designs are needed to strengthen the evidence on whether physical
fitness training can positively affect injury incidence in dancers.
